I wrapped mine in Aluminum Foil. Very classy and very Cool.
Also, I al looking at getting the Gold Foil Sheets one day and using them.
With the Aluminum Foil, you have a shiny back, a dull back, or even a "crinkle" back. the options are up to you. And with the Holidays approaching, they usually offer color foils, that will help you rock the iMac with style.
😛